A second Pennsylvania poll now has Barack Obama caught up with Hillary Clinton. In a survey conducted April 2, InsiderAdvantage says Clinton leads Obama 45 percent to 43 percent with 12 percent undecided. The margin of error is 3.7 percent.

A survey released yesterday by Public Policy Polling caught a lot of people by surprise when it put Obama ahead 45 percent to 43 percent. It’s survey was conducted April 1. There have been three other polls this week – one by Quinnipiac conducted in late March that had Clinton ahead by 9 points and still running strongly; and a pair by Rasmussen Reports and SurveyUSA that had her ahead by 5 and 8 points respectively, but noted signs of erosion. Prior to that, Clinton had enjoyed double-digit leads in the state in just about every poll.

Matt Towery of InsiderAdvantage said, “This could be the beginning of the end of the Clinton campaign. The crosstabs show Obama trailing among white voters, but by only a 49%-40% margin. More importantly, Obama has a lead among African-American voters of 56%-29%, with the remainder undecided.”

Clinton is under intense pressure to win big here, which is one reason that Obama may have decided to make a big push in a state where she started out with a commanding lead. If Obama wins or Clinton ekes out only a close victory, Obama would preserve his lead in popular votes and delegates.